MXPA99001093A - Load monitoring and management in a cdma wireless communication system - Google Patents

Abstract

A system and method for monitoring and managing the loading conditions in a CDMA wireless communication system (100). The system comprises a load monitoring device (102) such as a CDMA mobile station (104) connected to a data logging and processing device (106) such as a diagnostic monitor. The monitoring device (102) is placed within the service area of a base station (112). The monitoring device (102) periodically initiates a call, is assigned to a traffic channel normally, and logs a power control parameter such as mobile station transmit power or the number of closed-loop power control commands received per unit time. From this information, the load monitoring device (102) can infer the real-time traffic loading conditions of the base station (112). If the loading of the system exceeds a predetermined threshold, an alarm may be sent to the system management center (114) in order to take some action to limit additional loading on the base station (112).

Description

ADMINISTRATION AND LOAD MONITORING IN A CDMA-TYPE WIRELESS COMMUNICATION SYSTEM I. Field of the Invention The present invention relates generally to wireless communications. More particularly, the present invention is directed to a novel and improved system and method for monitoring and managing the load of a wireless communication system of the Code Division Multiple Access (CDMA) type.

II. Description of the Related Art In the field of wireless communication of the type of Code Division Multiple Access (CDMA), a broadband frequency channel is shared by multiple communication devices, each communication device uses a different propagation code of pseudoruide (PN). In a typical CDMA type wireless communication system, a first frequency band is used for uplink communications (from the base station to the mobile station), while a second frequency band, different from the first band of frequencies, is used. frequencies, it is used for the communications of the descending channel (from the mobile station to the base station). An example of this system is provided in the P1116 / 99MX U.S. Patent No. 4,901,307 entitled "SPREAD SPECTRUM MULTIPLE ACCESS COMMUNICATION SYSTEM USING SATELLITE OR TERRESTRIAL REPEATERS", issued February 13, 1990, assigned to the assignee of the present invention and incorporated herein by reference. The key to the concept of maximizing system capacity in a wireless communication system of the CDMA type, as described above, is the power control process. The output power of the subscriber units must be controlled to ensure sufficient strength of the signal received at the base station and to maintain good audio quality while minimizing the power for interference. Because a broadband channel of the CDMA type is reused in each cell, the self-interference caused by the other users of the same cell and the interference caused by the users in other cells is the factor that most limits the capacity of the system. Due to fading and other damage to the channel, maximum capacity is achieved when the signal to noise ratio (SNR) of each user is, on average, at the minimum necessary to support an "acceptable" channel performance. Since the spectral density of the noise is generated almost completely due to the interference of P1116 / 99MX other users, all signals must reach the CDMA receiver with the same average power. In the mobile propagation environment, this is achieved by providing dynamic power control of the mobile station transceiver. The power control protects against changes in the load, bottleneck in the system, slow and fast variations in the conditions of the channel and sudden improvements or degradations in the channel (darkening). The control of the transmitter power of the mobile station consists of two elements: the open loop estimation of the transmission power by the mobile station and the closed loop correction of the errors in this estimate by the base station . In the open-loop power control, each mobile station estimates the total power received in the assigned CDMA frequency channel. Based on this measurement and a correction provided by the base station, the power transmitted by the mobile station is adjusted to match the estimated path loss to reach the base station at a predetermined level. All mobile stations use the same process and arrive with equal average power to the base station. However, uncontrolled differences in the ascending and descending channels, such as the opposite fading that can occur due to the difference in P1116 / 99MX frequency and mismatches or mismatches in the reception and transmission chains of the mobile station, can not be estimated by the mobile station. To reduce these residual errors, each mobile station corrects its transmission power with the closed-loop power control information supplied by the base station by the low-speed data inserted in each upstream channel. The base station derives the correction information by monitoring the quality of the downstream CDMA channel of each mobile station, compares this measurement with a threshold and requests either an increase or a decrease, depending on the result. In this way, the base station maintains each downstream channel and, thus, all downstream channels, at a minimum received power necessary to provide acceptable performance. An example of a communication system using the open-loop and closed-loop power control methods described above is provided in U.S. Patent No. 5,056,109 entitled "METHOD AND APPARATUS FOR CONTROLLING TRANSMISSION POWER IN A CDMA CELLULAR MOBILE TELEPHONE SYSTEM ", assigned to the assignee of the present invention and incorporated herein by reference. In a CDMA wireless communication system, as described above, a number P1116 / 99 X predetermined radio frequency resources, such as transceivers and channel modulators / demodulators (modems) are located at each base station. The number of resources allocated to a particular base station is a function of the anticipated traffic load conditions. For example, a system in a rural area can have only one omnidirectional antenna in each base station and enough channel modems to support eight simultaneous calls. On the other hand, a base station in a dense urban area may be co-located with other base stations, each having several highly directional antennas and enough modems to handle forty or more simultaneous calls. It is in these denser urban areas that cell site capacity is in high demand and should be closely monitored and managed in order to provide the most efficient allocation of limited resources while maintaining an acceptable quality of communications. The sector / cell load is the proportion of the real number of users in the sector to the maximum theoretical number that the sector can support. This ratio is proportional to the total interference measured in the sector / cell receiver. The maximum number of users that the sector / cell can support is a function of the added signal-to-noise ratio of the activity P1116 / 99MX voice and interference from other cells. The signal to noise ratio of the individual subscriber unit depends on the speed of the subscriber unit, the radio frequency propagation environment and the number of users of the system. The interference from other cells depends on the number of users in these cells, the losses by propagation of the radiofrequency and the way in which the users are distributed. Typical capacity calculations assume an equal signal-to-noise ratio for all users and nominal values of voice activity and interference from other cells. However, in real systems, the signal to noise ratio changes from one user to another and the frequency of reuse or reuse of the frequency varies from one sector to another. Hence, there is a need to continuously monitor the load of a sector or a cell. A conventional way of monitoring cell site load conditions is for a person, usually a technician or network engineer employed by the wireless communication service provider, to travel from cell to cell taking readings of the load condition, using equipment specially designed and expensive test. The recorded data is then returned to a central processing facility for the post- P1116 / 99MX processing and analysis. Some significant disadvantages of this method are that the data can not be evaluated in real time and that important errors are introduced, due to the propagation effects between the base station and the measurement equipment. Thus, this monitoring method only provides a rough estimate of cell site load conditions and can only be used in a delayed manner to take corrective action, such as reallocating resources for the future. It does not allow the service provider to take any action in real time to improve the load conditions and their effect on the performance of the system. Additionally, it requires that a person travel in series to each site, thus providing an estimate of the "success or error" of the peak load conditions, and the consequent performance of the system that depends on whether the visit coincided with the times of Use real spikes (instead of assumptions). Another possible way to monitor cell site load conditions is to access the performance data recorded by the base station itself or by the base station controller. However, this requires that the scarce processing resources of the base station be diverted to collect and retrieve the data. Additionally, this P1116 / 99 X suffers from post-processing problems in non-real time as previously mentioned. Finally, it also requires that a person visit each cell site in series to retrieve the data. What is needed is a simple and accurate real-time remote monitoring and management system that does not require access to the base station or to the data recorded by the base station controller and, therefore, does not have a impact on processor performance.

SUMMARY OF THE INVENTION The present invention is a novel and improved system and method for monitoring and managing or managing the load conditions in a wireless communication system of the CDMA type. The system and the method use the uplink data collected by the mobile station to estimate the effect of the load on the performance of the system. By knowing the effect of the load on the performance of the system, some measures can be undertaken to limit access to the system or to allocate more resources in order to avoid degradation of system performance. The system comprises a load monitoring device, such as a CDMA mobile station P1116 / 99MX connected to a data recording and processing device, which may be a diagnostic monitor or a modified mobile station capable of performing the same data recording and processing functions. The monitoring device is placed within the service area of a base station. The monitoring device periodically initiates a call, is normally assigned to a traffic channel and records the following data: 1) the downlink transmission power of the mobile station, measured at the antenna connector in dBm, 2) the power received in the mobile station in the uplink as measured in the antenna connector in dBm; and 3) the closed-loop power control commands received from the base station per unit of time. From this information, the load monitoring device can infer the real-time traffic load conditions of the base station. In the preferred embodiment, the load monitoring device is connected by cables to the base station in order to avoid the errors introduced by the variation of time in the effects of aerial or air propagation. The above information is measured during the hours of peak use and during off-peak hours. In the preferred embodiment, the load monitoring device originates a call every thirty minutes with a duration P1116 / 99MX Two minute call During this time, the device has control of the traffic channel, continuously measures the transmission power of the mobile station and averages it to obtain an average transmission power of the mobile station. By comparing the average transmission power measured at peak hours with the measurement in off-peak hours, the load monitoring device can infer the effect of the load on the performance of the system. In alternate modes, the load monitoring device measures other parameters related to the power, such as the closed-loop power control commands and averages them to obtain an average value of the transmission gain setting namely variable. The adjustment of the transmission gain can then also be used to infer the effect of the load on the performance of the system. The load monitoring device also passes this data in real time to the system resource management station, where appropriate action can be taken based on the effect of the load on the performance of the system. For example, the load monitoring device can be used to automatically send an alarm or report to the system resource management center, if the performance of the P1116 / 99MX system degrades beyond a predetermined threshold. This alarm can be used to produce corrective action in real time, such as the rejection of additional access to the base station by other mobile stations or, to produce only graphical representations of the effect of the load on the performance of the system in a In addition, real-time data can be used to allocate resources more efficiently among the base stations of a system.

BRIEF DESCRIPTION OF THE DRAWINGS The particularities, objects and advantages of the present invention will be more evident from the detailed description set forth below, when considered together with the drawings, in which similar reference characters are identified in a manner corresponding in all of these and, where: Figure 1 illustrates a high level overview of the system of the present invention; Figure 2 is an illustration of selected portions of the load monitoring device of the present invention; and Figure 3 illustrates the method of the present invention.

P1116 / 99MX DETAILED DESCRIPTION OF THE PREFERRED MODALITIES I. Analysis The present invention depends on the behavior of the base station during various degrees of traffic load. Specifically, as more mobile stations transmit over the common CDMA traffic channel, the less sensitive the base station becomes to any individual transmission by a mobile station and, thus, the more aggressively it must perform the loop power control closed to ensure that all transmissions from the mobile station reach the base station with equal average power. Thus, if a given mobile station were stationary and, additionally, unaffected by the time variation of the propagation effects (i.e., wired to the base station), then the loop power control commands closed that receiving it from the base station would be controlled only by the load of the downlink CDMA channel and not by variations in the downlink power of that mobile station, as received at the base station (which would otherwise be constant ). Thus, in the present invention, the load monitoring device can infer the effect of the system load on the performance of the system from the difference between its P1116 / 99MX own transmission power and the transmission gain adjustment commands of the base station. The sensitivity, in dBm, of a base station to the downlink transmissions by the mobile station is provided by: where NF is the data or noise figure of the base station in dB, BX is the ratio of the energy per bit of the Downlink information bits at the broad band CDMA spectrum density in dB and XL is the system load in dB. In other words, XL equals 10 [log (1-X)], where X is the ratio of the number of simultaneous mobile stations in t the downlink CDMA channel to the maximum theoretical number of mobile stations that can support the downlink CDMA channel. The sensitivity of the base station is the threshold, in dB, at which the base station can adequately receive the downlink transmission from the mobile station. In this way, as can be seen, as the load of the XL system increases, the sensitivity of the base station decreases. The transmit power of a mobile station of controlled power is equal to the sensitivity of the P1116 / 99MX base station minus the loss of the downlink path. That is, the mobile station must transmit at a sufficiently high power level to overcome the path loss of the downlink and still reach the base station at an acceptable level. In mathematical terms: Rs = S + I? (2) where Pts is the transmit power of the mobile station, as measured at the antenna connector, in dBm, S is the sensitivity of the base station as defined in Equation (1) and Ifp is the path loss of the downlink between the antenna connector of the mobile station and the receiving antenna connector of the base station, in dB. This factor includes loss of propagation, antenna gain and feeder loss. By replacing Equation (1) and (2), the system load can be written in terms of the transmit power of the mobile station as: XL = 134 - NF - E N / o + Pts - Lpr (3) The quantities? F, Ip and Eb /? 0 are constant and do not depend on the load conditions, hence, the P1116 / 99MX Equation (3) can be rewritten as: XL = C + Pts (4) where C is a constant and Pts is the transmission power of the mobile station measured at the antenna connector in dBm. Thus, by replacing Equation (4) in Equation (3): C = 134 - NF - Eb / j - Lp (5) Note that here Eb /? 0 is considered as constant, since, in the preferred embodiment, the load monitoring device is connected by cable to the base station under consideration and, thus, is not susceptible to variation in time caused by the change in propagation effects. Since Equation (5) is true all the time, then the difference of the effect of the charge between two separate measurement periods can be written as: XL (t 2) - XL. { t l) = Pts (t 2) - Pts (t l) (6) where t ^ and t2 are two different measurement times either. In this way, the transmission power of the Pts unit during an out-of-peak period of use can be compared with that of the peak period of use to determine P1116 / 99MX the effect of the load on the performance of the system. In other words, the adjustment in the average transmission gain can be used to determine the effect of the load on the performance of the system. Referring again to Equation (3), there is also a path loss in the uplink, which is equal to the uplink power received by the mobile station minus the uplink power transmitted by the base station. In mathematical terms: Lí = P: P, '(7; f wherein LX is the loss of the uplink path between the transmit antenna of the base station and the antenna connector of the mobile station, in dB, Ps is the uplink reception power of the mobile station, measured in the antenna connector, in dBm and P is the transmit power of the base station measured in the antenna connector, in dBm. By invoking the reciprocity theorem, which says that the average loss of the uplink path equals the average loss of the downlink path, the system load can be expressed in terms of the power of the downlink transmitted by the downlink. mobile station, the power of the uplink P1116 / 99MX received by the mobile station and the uplink power transmitted by the base station, substituting equations (3) and (7): XL = 134 - NF - Eb / N + Pts + Prs - Ptb (8) But since the mobile station uses the closed-loop transmission gain adjustment commands to calculate its transmit power, Equation (8) is written more conveniently as: where Tadj is the transmission gain setting in dB of the mobile unit in response to the closed-loop power control commands transmitted by the base station and k is the standby or inversion factor that the mobile station is using to calculate the open loop transmission power. Note that even when in Equation (7) the reciprocation of the uplink and downlink path losses was assumed, any errors in this assumption are compensated for by the closed-loop power control commands and thus are reflected in Tacj-,. By replacing Equation (8) and (9), the load of the base station can then be written in terms of the P1116 / 99MX transmission gain adjustment, Tadj, as follows: XL = 134 NF 'Nr + k + T ad f (10) which can be rewritten conveniently as: XL = C + Tadj (11) where C is a constant provided by: C = 134 - NF - Eb? + k - Pf (12) Since Equation (12) is true at all times, then the difference of the charge effect between two separate measurement periods can be written as: XL () - ^ L () = tadj (t2) - tadj (tl) (13) where t2 and t] _ are two different measurement times either. In this way, the Tadj during a period of off-peak use can be compared with that of a peak period of use to determine the effect of the load on the performance of the system. Clearly, there are many parameters related to the power that can be measured in order to compare the load of the system at some point with the load of the system at another time. For example, the above analysis can be performed to obtain a load ratio expressed in terms of the P1116 / 99MX power received at the mobile station.

II. System ^ Load Monitoring Method The relationship identified in Equation (6) or (13) above, is exploited in the present invention to provide monitoring and real-time management of the system load. Figure 1 illustrates a high level overview of the system 100 of the present invention. The base station of CDMA 112 is observed to be in wireless communication, via antenna 110, with four exemplary mobile stations 108a-108d. Mobile stations 108a-108d, for example, are controlled-power CDMA cellular radiotelephones, as is known in the art. The base station 112 is also in periodic communication with the load monitoring device 102, which may comprise an ordinary controlled power CDMA cellular radiotelephone 104, coupled to a data recording and processing device 106, such as a data recording device. CDMA diagnostic monitor or other data processing device as is known in the art. Alternatively, the load monitoring device 102 may be a specially modified mobile station containing a microprocessor programmed to perform the data recording and processing functions. P1116 / 99MX In the preferred embodiment, the load monitoring device 102 is wired to the base station 112 by means of the cables 116 in order to minimize any variation in time of both propagation effects and Eb / N0 in the data recorded by the load monitoring device 102. However, in alternate embodiments, the load monitoring device 102 may be stationary, while wireless communications are initiated with the base station 112 to record the relevant data described below. The base station 112 is also in communication with the system administration center 114, wherein reside any personal and network computers required to perform the monitoring of failure, diagnosis and administration of the base station 112. In Figure 1, the base station 112 passes the operating parameters of the system and the alarms to the system administration center 114 by means of the cables 118. However, in alternate modes, the base station 112 may communicate with the system administration center 114 using any haul communication method as is known in the art, such as It can be wireless microwave communication from point to point. In the normal operation of the system 100, the P1116 / 99MX mobile stations 108a-108d, communicate periodically with the base station 112, either to originate a call, to receive (terminate) a call or to send or receive various supplementary messages to or from the base station 112. During the peak usage hours, such as for example, during the half day, one can expect that the four mobile stations 108a-108d, are in simultaneous communication with the base station 112, thereby increasing the load on the system and the interference at downlink. Conversely, during off-peak hours, such as at midnight, one can expect only one of the mobile stations 108a-108d to be in communication with the base station 112 at any given time, thereby decreasing the system load. Note that there may be a smaller number or much more than four mobile stations communicating simultaneously with the base station 112, depending on the capacity of the base station 112. However, for reasons of simplicity, Figure 1 is illustrated only with four mobile stations 108a-108d. Additionally, the load monitoring device 102 periodically originates a call with a predetermined length to the base station 112, in accordance with a predetermined scheme. In the modality ! _5 preferred, load monitoring device 102 initiates P1116 / 99MX a two-minute call to the base station 112 every thirty minutes during both peak and off peak times. Clearly, this predetermined scheme can be varied both in duration (with shorter or longer times at two minutes) and in frequency (less than thirty minutes or more than these), depending on the monitoring and administration needs of the center 114 system administration. In the preferred embodiment, a two-minute call duration was selected, because it is close to the average duration of a call from a real cellular radiotelephone. Additionally, the frequency of once every thirty minutes can be selected as a concession or commitment between the resolution of the data and the amount thereof. When any of the mobile stations 108a-108d is communicating with the base station 112, the base station 112 transmits closed-loop power control commands to the active mobile stations 108a-108d, as described in the above-mentioned Patent of the States. United No. 5,056,109. Each of the closed-loop power control commands transmitted to the various active mobile stations 108a-108d directs the particular mobile station to either increase or decrease its transmit power by an amount in the P1116 / 99MX order of 1 dB, in order that each signal transmitted from the mobile station reaches the base station 112, so that the signal to noise ratio or E ^ / NQ is sufficient to ensure a minimum quality of Required voice Additionally, each time the load monitoring device 102 communicates with the base station 112, the base station 112 similarly transmits the closed loop power control commands to the load monitoring device 102, because for the base station 112 appears merely as another mobile station. Referring now to Figure 2, an illustration of selected portions of the load monitoring device 102 is shown. The radio frequency (RF) signals that include both modulated information and closed-loop power control commands are received by the load monitoring device 102 on the antenna 200. Again, note that in the preferred embodiment, the signals transmitted to the device 102 load monitoring by the base station 112 (see Figure 1), through the cables 116 are directly coupled to an antenna port of the load monitor 102. However, in alternate modes, the monitoring device 102 load uses a normal antenna 200 as is known in the art. The received signals are routed or routed P1116 / 99MX by the duplexer 202 to the low noise amplifier (LNA) 204, where the front end gain is adjusted. Then, in the automatic gain control amplifier (AGC) 206, the power level of the intermediate frequency (IF) is adjusted. The intensity of the received signal is measured in the intensity indicator of the received signal (RSSI) 212, which uses the intensity of the received signal to generate an open loop power control signal 214. Additionally, the received signal is sampled in the analog to digital converter 208 and then digitally demodulated in the demodulator 210. The closed-loop power control commands 216 are supplied to the combiner 228, where they are combined with the open-loop power control signal 214 and are used to adjust the transmit power of the power amplifier (PA) 220. In the preferred embodiment, the data processor 218 records the output power of the PA 220, the scale to represent the output power as measured at the connector of the antenna 200. In the preferred embodiment, the data processor 218 accumulates the measurements of the output power on the data line 232 over the two-minute call ation and averages them to obtain the average transmit power of the mobile station.

P1116 / 99MX In an alternate mode, the closed-loop power control commands 216 from the base station 112 are extracted from the demodulated signal and recorded by the data processor 218. In this alternate mode, the data processor 218 accumulates the closed-loop power control commands on the two-minute call and averages them to get TADJ. Since the CDMA frame has a duration of 20 ms and the base station can send a closed-loop power control command per frame, the TADJ will be based on 6,000 individual power adjustment values. Higher order statistics can also be generated. The data processor 218 may be an integral part of a modified mobile station or may be a separate data recording and processing device, such as a CDMA diagnostic monitor, as is known in the art. The data processor 218 compares the average transmission power (or alternatively, the average TADJ value) generated for an out-of-peak period of use with the average transmission power (or alternatively, the average TADJ value) generated to the peak usage period. to determine the difference in system load as derived in equations (6) or (13). Based on this information, the data processor 218 can send an alarm signal u P1116 / 99MX another informative signal 230 to the system administration center 114 (see Figure 1) for the appropriate action. The alarm signal or other information signal 230 can be used to produce reports on the state of the system load or to take action in real time, such as denying additional access to the system if the load exceeds a certain threshold. Figure 3 illustrates the method of the present invention. The method begins at block 302 where the load monitoring device originates a call to the base station during an out-of-peak TI time. For the duration of the call which in the preferred embodiment is two minutes, the load monitoring device measures a parameter related to the power, which may be already: the transmission power of the mobile station in the preferred mode or , the TADJ (T1) in an alternate mode, in block 304. The load monitoring device then originates a call to the base station during a peak time T2 in block 306 and measures the same parameter related to the power so The call lasts in block 308. In block 310, the load monitoring device then calculates XL (T2) - XL (T1) as defined in either Equation (6) or (13) and compares it with a predetermined threshold of Y dB in block 312. The threshold Y can be determined individually for P1116 / 99MX each base station depending on the desired performance of the base station. If the difference XL (T2) - XL (T1) calculated in block 310 is greater than the predetermined threshold Y, then the load monitoring device sends an alarm to the system administration center in block 314 and the actions are performed appropriate, such as may be, denying additional access to the system. In this case, the load monitoring device will then start the process again in block 302. If the difference XL (T2) - XL (T1) calculated in block 310 is less than the predetermined threshold Y, then the monitoring device load does not send an alarm and, only the process starts again in block 302. In other modalities, modifications are made to the flow of Figure 3 to customize or adapt the method to various applications. For example, the load monitoring device may originate several calls in blocks 302 and 306, each separated by thirty minutes, during peak and off peak times in order to obtain averages. Additionally, the load monitoring device can be configured to send the information to the system administration center without considering whether the load exceeds the predetermined threshold. This information could be useful for P1116 / 99MX generate, for example, a graph of the time against the load for a daily operation cycle. Clearly, many adjustments can be made to both the programming and the use of the information without deviating from the spirit of the present invention. The prior description of the preferred embodiments is provided to enable any person skilled in the art to manufacture or use the present invention. The various modifications to these modalities will be readily apparent to those skilled in the art and the generic principles defined herein may be applied to other modalities without the use of the inventive faculty. Thus, it is not intended that the present invention be limited to the embodiments shown herein but be in accordance with the broadest scope consistent with the novel principles and features disclosed herein.

P1116 / 99MX

Claims (10)

1. NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and, therefore, the content of the following CLAIMS is claimed as property: 1. A system for determining the load in a base station of the CDMA type, which transmits closed-loop power control commands, the CDMA base station is controlled by a system administration center, the system comprises: a CDMA communication device having a transmission circuit to originate a communication with the base station of CDMA, in accordance with a predetermined scheme or program and having a receiving circuit for receiving the closed-loop power control commands; a data processor, coupled to the reception circuit, for recording a power control parameter and for transmitting a data signal to the system administration center, in response to received closed-loop power control commands. The system according to claim 1, wherein the CDMA communication device originates a communication with the CDMA base station during a first period and during a second period and, where the P1116 / 99 X data processor transmits an alarm signal to the system management center if the difference between the power control parameter during the first period and the power control parameter during the second period exceeds a predetermined threshold. The system according to claim 2, wherein the administration center of the system avoids further charging to the base station in response to the alarm signal. . The system according to claim 3, wherein the data processor is a CDMA diagnostic monitoring device. 5. A method for determining the load on a CDMA base station, which transmits closed-loop power control commands, the CDMA base station is controlled by a system administration center, the method comprising the steps of: originating a communication with the CDMA base station, in accordance with a predetermined scheme or program; receive the closed-loop power control commands; register a power control parameter; and transmit a data signal to the system administration center in response to the commands of P1116 / 99MX closed loop power control received. The method according to claim 5, wherein the step of originating further comprises causing a communication with the base extraction of CDMA during a first period and during a second period and, wherein, the step of transmitting comprises further transmitting a alarm signal to the system administration center if the difference between the power control parameter during the first period and the power control parameter during the second period exceeds a predetermined threshold. The method according to claim 6, further comprising the step of avoiding, from the administration center of the system, the additional loading of the base station in response to the alarm signal. 8. A load monitoring device for use with a CDMA base station, which transmits closed-loop power control commands, the CDMA base station is controlled by a system management center, the load monitoring device comprises : a transmission circuit for originating a communication with the CDMA base station in accordance with a predetermined program or scheme; a receiving circuit to receive the P1116 / 99MX closed-loop power control commands; a data processor, coupled to the reception circuit, for recording a power control parameter and for transmitting a data signal to the system administration center, in response to received closed-loop power control commands. 9. The load monitoring device according to claim 8, wherein the transmission circuit originates a communication with the CDMA base station during a first period and during a second period and, where, the data processor transmits an alarm signal to the system administration center if the difference between the power control parameter during the first period and the power control parameter during the second period exceeds a predetermined threshold. 10. The charge monitoring device according to claim 9, wherein the administration center of the system avoids further charging to the base station in response to the alarm signal. P1116 / 99MX, «- < ? 33 SUMMARY OF THE INVENTION A method and system for monitoring and managing the load conditions in a wireless communication system type CDMA (100) are described. The system comprises a device for monitoring load (102), for example a CDMA mobile station (104) connected to a data processing and logging device (106) such as a diagnostic monitor. The monitor device (102) is placed within the area of 10 service of a base station (112). The monitor device 102 periodically initiates a call, is normally assigned to a traffic channel and chronologically records a power control parameter, for example the transmit power of the mobile station or 15 the number of closed-loop power control orders received per unit of time. From this information, the load monitor device (102) can infer real-time traffic load conditions for the base station (112), if the system load exceeds At a predetermined threshold, an alarm may be sent to the system administration center (114) in order to take some action to limit the additional load on the base station (112). P1116 / 99MX